基于牙体牙髓、牙周及功能健康的显微微创牙体预备

牙体预备技术是口腔美学修复治疗必知必会的核心操作,通过一定量的牙修复体组织的磨除,为目标修复体提供容纳空间、粘接面与完成线等。如何在完成高质量牙体预备的同时还能保存牙体、保护活髓和牙周组织是美学修复牙体预备中亟需解决的难题。本文就微创牙体预备的概念及核心要素,显微牙体预备涉及的解剖生理学、显微牙体预备术前设计进行介绍,并总结了显微牙体预备技术临床路径,提出了显微牙体预备核心因素——量与形的新认知。     

显微牙体预备手术操作规范

牙体预备手术是口腔修复治疗不可或缺的核心操作,显微牙体预备手术可提高牙体预备的精确性和预备质量。中华口腔医学会口腔修复学专业委员会组织专家,制定显微牙体预备手术操作规范,标准化该技术的设计要点和操作流程,突出其与传统裸眼水平下牙体预备手术的区别,以促进显微牙体预备手术的推广和应用。     

显微牙体预备手术操作规范

牙体预备手术是口腔修复治疗不可或缺的核心操作,显微牙体预备手术可提高牙体预备的精确性和预备质量。中华口腔医学会口腔修复学专业委员会组织专家,制定显微牙体预备手术操作规范,标准化该技术的设计要点和操作流程,突出其与传统裸眼水平下牙体预备手术的区别,以促进显微牙体预备手术的推广和应用。     

《牙体预备基本原则》

广大口腔医学工作者期待已久的、从国际精萃出版集团（Intemational Quintessence Publishing Group）引进的《国际牙科名著系列》之一的《牙体预备基本原则》已翻译出版发行，该书叙述了牙体预备的重要意义，重点介绍了铸造金属和瓷修复体牙体预备的基本原则、各个环节的操作，同时对牙体预备常用的器械及特殊情况下的牙体预备方法进行了介绍。     

目标修复体空间的内涵、分析设计及临床转移实施

目标修复体空间是修复治疗计划中必须要获得的,符合理想美学形态和功能的修复体应占据的牙体内或牙体外的空间。在保证最小量的目标修复体空间的情况下,微创修复理念才能成功;而精准微创的牙体预备必须依据目标修复体空间的分析设计和美学转移导板指示才能真正实现。本文介绍了目标修复体空间的概念、分析设计和临床转移实施方法,为全面深刻地理解精准微创的牙体预备修复技术提供指导。     

牙体预备前后牙髓血氧饱和度初步观察

口腔修复技术中,保留基牙健康的牙髓,能预防牙折,延长修复体的使用寿命,而如何客观、准确检测到牙体预备对牙髓活力的影响;怎样保持牙髓的健康活力是修复医师面临的挑战。本研究应用脉搏血氧测定仪初步观察牙体预备前、后牙髓SO2变化。     

薄型瓷贴面牙体预备术式的分型探讨

薄型瓷贴面是国外治疗变色前牙、染色前牙和前牙小缺损的常规修复方法,国内的临床报表表明瓷贴面明显优于树脂贴面,瓷贴面牙体预备术式的分型目前尚有争议,国外的六型分类法指标多,难于掌握,作者设计了三种牙体预备术式,并用于７８颗上前牙修复,考查粘贴牙的美学效果,探索薄型瓷贴面牙体预备术式新的分型方法,结果表明三型分类法简明扼要,适应范围明确,容易理解,掌握和应用。     

全冠的牙体预备

全冠的牙体预备是修复体能否成功的前提。本文从(牙合)面聚合度,(牙合)龈/切龈距离与颊舌径的比值,轴面、(牙合)面、切缘的切削量,预备体外形和表面质地、冠的边缘方面探讨全冠牙体预备时应遵循的原则,有助于临床提高冠、桥的修复质量。     

瓷贴面修复牙体不同预备类型比较的研究进展

瓷贴面因其种种优势,在前牙美学修复中占据了重要的地位。目前,牙体预备类型是学者们比较关注的一个方面,直接关系到修复体修复后的强度、颜色和形态等。但是,关于贴面的牙体预备,学者们尚未形成一致的观点,相关研究的结果也不尽相同。本文回顾了当前研究的现状,并就贴面修复牙体预备量、预备类型、相关体外研究和临床研究等方面展开讨论。     

关于牙体预备里的数字追问——从目测经验类比到数字引导

不同修复方式及材料选择、拟预备牙体本身条件等都会对牙体预备手术产生影响。为了牙体保存、活髓保护及牙周健康等共识理念的实现,牙体预备量总体越少越好已成共识。支撑其实现的条件一是备选修复材料的综合性能进步、材料所需承载空间有效减少;二是预备量和形的数字化分析及实测技术的出现,使得导板下备牙量与修复空间全程实测核查成为可能,预备手术的引导方式也从凭借个人经验累积的目测徒手操作,发展到了采用数字引导联合显微操作进行等。这些进展也标志着精准的、可全程实测核查的引导式修复学的形成。本文将从数字化修复、引导式口腔修复及显微修复技术的视角,对牙体预备的数值要求与数量关系转移展开数字追问;并从测量四要素对现有数值要求做论证评价,指出统一测量方法、研发百微米、十微米级及角度的测量工具将是解决数据可信度的重点;同时也对牙体预备量的引导方式进行归纳梳理,进一步解读了为什么目测经验类比为逻辑基础的当前主流修复技术基础无法有效支撑数字化修复的原委,强烈呼吁尽快打造口腔修复的数字基础。     

无髓后牙全瓷高嵌体修复的研究进展

无髓后牙的微创修复是临床研究的一个热点,近年来,随着粘接技术及全瓷材料的发展,高强度全瓷高嵌体因其微创、美观、对机械固位要求较低等优势,在后牙根管治疗后的修复中应用逐渐广泛。本文从材料、牙体预备、粘接及其临床应用注意事项等方面,对全瓷高嵌体在无髓后牙牙体缺损修复中的应用进展进行综述,以期为临床工作提供参考。     

目标修复体空间指导多学科联合治疗精准修复1例

冠、桥修复需要对基牙进行定量调磨,如何更加精准地进行牙体的定量预备是微创修复追求的目标之一。本文报道1例上、下颌侧切牙先天缺失的病例,以目标修复体空间（TRS）为指导,在正畸、牙周多学科联合治疗后,制作个性化牙体预备数字化导板辅助精准牙体预备,完成固定桥修复,最终为患者恢复了上颌牙列的完整、美观和功能。该病例提示,在TRS指导下,牙体预备数字化导板能有效提高牙体预备的准确性。     

Coronal tooth structure in root-treated teeth prepared for complete and partial coverage restorations

Summary  This in vivo study assessed the remaining coronal tooth structure in teeth prepared for complete and partial coverage restorations using 3D-scanning and a Tooth Restorability Index (TRI). The cuspal coverage preparation designs selected by 10 postgraduate dentists and 10 general dental practitioners were recorded in a questionnaire. Eighteen patients had molar root treatment completed at the Eastman Dental Hospital and were prescribed a coronal-radicular amalgam core and cast restoration. Each tooth was prepared in vivo by one operator for a cast restoration. Two clinical impressions were made to produce two dies: one of remaining coronal tooth structure before crown preparation and a second die of coronal tooth structure in vivo after crown preparation. For teeth prepared for partial coverage in vivo ( n  = 13), a third die was prepared in vitro representing remaining tooth structure after complete coverage preparation. The three dies were of tooth structure prior to core placement. All dies ( n  = 31) were scanned using a laser profilometer and the volume of remaining tooth structure calculated. Four observers scored 31 dies using the TRI. The percentage loss of coronal tooth volume following a complete instead of a partial coverage preparation varied from 3·29% to 45·23% and the mean TRI fell from 10·7 to 7·5 units. There was a strong correlation between mean TRI and scanned volume of tooth structure ( P  = 0·013). Over 50% of the dentists altered their initial choice of restoration design from complete to partial coverage. Complete coverage preparations removed more tooth structure than partial coverage.     

Training in tooth preparation utilizing a support system

Tooth preparation is an essential technique for dental treatment, but it is a skill not easily learned by a dental student. To facilitate this leaning process, a new tooth preparation support system with a parallel link mechanism was developed. This study reports the educational efficiency of this system for dental students. Dental students with no experience in clinical practice were selected and divided into two groups; one trained with this support system; and the other, with freehand preparation. They prepared axial walls in right maxillary second premolars and molars mounted in a phantom manikin with an air-turbine handpiece. Convergence angles of the axial walls and parallelisms between axes of prepared teeth were evaluated. Training with the support system led to significantly smaller convergence angles and parallelisms as compared with freehand preparation training. With the freehand preparation after training, the convergence angles and parallelisms became smaller in the group trained with the support system than those trained with freehand. The above findings suggest that training in tooth preparation utilizing the newly developed support system can be one of practical programs that are useful for dental students to achieve greater competency in tooth preparation.     

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随着材料科学和牙科义齿制作技术的发展,牙科陶瓷材料在口腔美学修复中的应用越来越广泛。本文介绍了当前不同瓷修复体——瓷贴面、瓷嵌体、全瓷冠修复中基牙预备的特点,拟为口腔修复医生在临床牙体预备中提供参考。     

目标修复体空间中的数量及数量关系在精准美学修复中的应用

目标修复体空间是指拟定的修复后各种修复体所占据的最小空间,也是口腔修复治疗在分析与实施阶段中必须要获得的、符合理想美学形态和功能的未来修复体所占据的牙体内部或牙体外部的空间。精确的目标修复体空间数量分析设计是微创牙体预备的前提,而准确的目标修复体空间数量转移实施是保证最终修复效果的关键。本文提出了在不同的目标修复体空间分类情况下,利用目标修复体空间的数量计算方法、数学关系的分析设计,以及转移实施阶段各关键数量的控制方法,进一步阐述了精准与微创的关系,有助于深入理解和实施精准美学修复。     

Comparative evaluation of the impact of minimally invasive preparation vs. conventional straight‐line preparation on tooth biomechanics: a finite element analysis

Minimally invasive endodontics emphasizes preservation of a maximal amount of healthy tooth tissue. However, whether the tooth structure preserved by minimally invasive endodontics can maintain higher fracture resistance is unclear. This study aimed to compare the biomechanics on teeth after minimally invasive (MI) preparation and straight‐line (SL) preparation using finite element analysis. Six finite element analysis models of a mandibular first molar were constructed and divided into two groups (MI and SL). Two loads of 250 N, one vertically stimulating the vertical masticatory force and the other given 45° to the longitudinal axis of the tooth, were applied. Stresses in the teeth were calculated and analyzed. Under both vertical and 45° loads, the greatest stresses were located at the margin of the cavities on the occlusal surfaces. The stress concentration areas of teeth with minimally invasive access cavities were smaller than those of teeth prepared with straight‐line opening in coronal and cervical areas. The stress concentration points in the cervical areas increased with the increase of canal taper in the coronal third. Minimally invasive access preparation reduced the stress distribution in crown and cervical regions. A smaller taper cervical enlargement caused lower stress in the cervical region.